The present invention generally relates to assembly fixtures and, more particularly, to an assembly cart for a large one-piece composite fuselage barrel and to a method for stabilizing large cured composite fuselage barrels.
In recent years, Boeing Commercial Airplanes has focused its new airplane product development efforts on the Boeing 7E7, a super-efficient airplane. In addition to bringing big-jet ranges to mid-size airplanes, the 7E7 will provide airlines with unmatched fuel efficiency, resulting in exceptional environmental performance. The airplane may use 20 percent less fuel for comparable missions than any other wide-body airplane. Furthermore, the airplane will be able to travel at speeds similar to today's fastest wide bodies, about Mach 0.85. Still further, the wide body aircraft 7E7 may provide 40 to 60 percent more cargo revenue capacity. The key to this exceptional performance is a suite of new technologies being developed by Boeing and its international technology development team. For example, the majority of the primary structure, including the fuselage and wing, on the 7E7 will be made of composite materials. Construction materials may be used (by weight) as follows: about 57% composite materials, about 24% aluminum, about 11% titanium, and about 8% steel. By volume, the 7E7 will be about 80% composite materials. Composite materials are significantly lighter than traditional aircraft materials, such as aluminum and aluminum alloys, titanium and titanium alloys, and steel. The use of composite materials will make the 7E7 a very light aircraft for its capabilities.
Since composite materials have material characteristics that differ from traditional aircraft materials it will not be possible to use existing facilities and equipment for the construction and assembly of the 7E7. For example, the large fuselage sections that will be made out of a composite material and which will have a one-piece barrel shape will be built on an inner mold line mandrel. After curing of the composite material, such as a graphite/epoxy, the inner mold line mandrel needs to be removed. The fuselage sections will be approximately 24 feet long and will have a diameter of about 19.5 feet and, therefore, are quite large. Furthermore, composite material in post-cure condition is not as stiff as traditional material, such as aluminum or titanium and their alloys, used to build fuselage sections. Furthermore, composite material in post cure condition will not be stiff enough to be moved around. Therefore, a large fuselage barrel having a diameter of about 19 feet and a length of at least 24 feet would collapse under its own weight if the inner mold line mandrel were to be removed without stabilizing or holding the fuselage barrel. Currently, no equipment exists that could hold or carry such large structure as the fuselage barrel of the 7E7. Furthermore, the 7E7 will consist of at least of 3 fuselage sections that need to be joined with each other. In order to join two adjacent fuselage barrels, the barrels will need to be moved toward each other and the barrels also will need to be aligned. Currently no equipment exists that would allow the transport and alignment of the large fuselage barrels. Since the different fuselage sections of a large new generation aircraft, such as the 7E7, for example, the aft section, the center section, and the forward section, will not have the same size, shape and fuselage features, equipment for carrying and holding these fuselage sections is needed that may be easily adjusted to the features of each fuselage section.
As can be seen, there is a need for developing new equipment that is able to stabilize, hold, and carry large fuselage barrels without frames having a diameter of about 19 feet and a length of more than 24 feet, such as the fuselage barrels of the 7E7 airplane. Furthermore, there is a need to prevent large one-piece composite fuselage barrels, such as the fuselage barrels of the 7E7, from collapsing under their own weight during removal of the inner mold line mandrel. Also, there is a need to provide new equipment for holding and carrying large fuselage barrels, such as the fuselage barrels of the 7E7, that may be easily adjusted to the size and shape of the fuselage barrel. Moreover, there is a need to provide equipment that allows the joining of adjacent fuselage barrels having a diameter of about 19 feet and a length of more than 24 feet.
There has, therefore, arisen a need to provide an assembly structure for large one-piece composite fuselage barrels having a diameter of about 19 feet and a length of more than 24 feet. There has further arisen a need to provide an assembly structure that has modular components, which are easily adjustable to the shape and size of a large one-piece composite fuselage barrel. There has still further arisen a need to provide a method for stabilizing large cured composite fuselage barrels.